With known processes and apparatus of this kind, the web is cut after the facing or laminating process. A register-controlled transverse cutter is required for this purpose, which correlates the cutting line with an image printed on the covering sheets. The printed image is scanned by the register-control device and the blades of the transverse cutter are displaced relative to each other in such a way that the cutting line is always the same distance from a printed registering mark in the printed image. Despite the high technology employed, however, the accuracy of this feed can only be achieved approximately. The high technology employed for scanning a printed registering mark is necessary since an unacceptable cumulative effect of the tolerances would result if, for example, the leading edge of the sheet were used instead as the reference for each processing step. The printing of the sheets, the application and mounting of the facing on the carrier web, the subsequent division of the faced web into separate faced sheets, and the placing of the faced sheets on objects for use as packing material, for instance, are all separate steps of this kind.
In the system on which the invention is based, in general, printed sheets are mounted as a facing on a carrier material in web form. There is also a system in which both the printed sheets and the carrier material are supplied to the facing station in cut sheet form. If, as in the other system, the carrier material is used in sheet form from the outset during the facing process, and particularly when corrugated paper which is covered over on one side is involved, problems arise, especially at high operating speeds, in the supply of the sheets and in the correlation of the carrier sheets and the covering sheets so that covering is effected accurately. In addition, when the adhesive is being applied, the leading edges of the individual carrier sheets have a tendency to stick to the adhesive applying roller. Machines have therefore been developed in which the corrugated paper sheets which are covered over on one side are passed through the adhesive applying device transverse to their direction of manufacture because these sheets then display a greater degree of rigidity in their direction of passage through the apparatus. However, this has the disadvantage that the amount of adhesive applied may be excessive, since the gap between the adhesive applying roller and the supporting roller has to be adjusted to the height of the smallest corrugation. Corrugation of normal height are therefore compressed beyond the normal amount, causing the adhesive to be forced away from the peaks of the corrugations. Apparatus has also been developed in which the carrier material in the form of sheets is passed in front of an adhesive applying roller by means of gripper devices. Gripper devices of this kind are expensive to produce, however, and are susceptible to becoming soiled. Apparatus in which the carrier material is passed along the adhesive applying roller in either a flat orientation or with a curvature that is opposed to the direction of curvature of the adhesive applying roller, also have the disadvantage that the contact time between the adhesive applying roller and the carrier material is only brief. In addition, a supporting roller is required. As already mentioned, the adhesive applying roller and the supporting roller have to be set to a particular gap, with the disadvantages which this entails.
It has also already been proposed to divide up the carrier weg into individual sheets after the adhesive has been applied, but before the facing process. But, since it is necessary for the cutting device to cut into the adhesive while it is still wet, after a short time, adhesive builds up on the blades, hardens there and prevents further trouble free cutting.